Hemp and flax, cultivated and used by humans since ancient times, are the two most sustainable fibres in the world. Versatile, resistant and ecological, both plants are nowadays undergoing a new process of revalorisation. Many consumers have become more aware of sustainability and are looking for natural fabrics. Although hemp and flax are very similar in appearance, they nevertheless have important differences. In fact, each has its own characteristics and applications that make them unique. In this article, we will analyse the main differences of these two fibres.

The main factors that distinguish the cultivation of hemp from flax (linen)

Often confused due to their similarity, hemp and flax are two natural plants that have a lot to offer. However, in order to make the most of their properties it is essential to know what the main differences are between the two crops, distinctions that end up influencing the way in which they must be cultivated and used by the textile industry.

1. Herbicides

Let's start the comparison by analyzing the use of herbicides. Hemp, thanks to its ability to resist diseases and its shading properties, does not need herbicides or fertilizers to be cultivated and obtain a good income. It is for this reason that the green gold plant has been nicknamed the crop par excellence of organic farming.

On the contrary, in order to survive and produce fibers, flax requires the use of herbicides that protect crops from infesting weeds given its poor shading capacity. In any case, it must be emphasized that the amount of herbicide treatments used in flax plantations are much lower than those used with cotton.

2. Pesticides

One of the main differences between the two plants has to do with the fact that textile hemp grows well without the need to use chemicals. In fact, it should be underlined that it is a plant that is not often attacked by parasites. This means that in itself, hemp does not require the use of pesticides and fungicides to be cultivated and offer a good yield.

In practice, as has been highlighted by M. Carus and S Piotrowski (2011) in Italy, the United Kingdom and Germany, no pesticides are used. Until now, only in France is a pesticide treatment applied every 8 years to prevent the propagation of the hemp beetle [1].

As for flax, it must be said that it is a plant that requires the minimum use of pesticides. Some of the insects that can affect the plant are moths and thrips. In any case, as Giampiero Maracchi (2007) points out, it is good to keep in mind that linen needs five times less pesticides than cotton.

3. Fibre yield

On the fibre yield side, hemp offers a higher fibre yield than flax. According to data from the latest harvests, hemp offers an average fibre yield of 220 to 365 kg while flax averages 150 to 210 kg on the same amount of land.

The scientific study carried out by Marie Grégoire (2021) showed that hemp is a source of high-performance textile fibre, i.e. with a higher level of productivity. Its production potential of long fibres per hectare is greater than that of flax, reaching a considerable difference of 20% more [2].

4. Effect on the soil - Phytoremediation

A further aspect to be analysed when comparing flax and hemp is the effect of the fibre on the soil. Experienced farmers in the field point out that hemp is very suitable for rotational cultivation. Very often, in fact, it is cultivated the year before the flax harvest because it prepares the soil by leaving it free of weeds, nematodes and fungi, enriching it instead with the nutrients it needs.

It should come as no surprise, then, that growers regard hemp as the plant that is good for the soil: not only does it aerate it, but it also helps to produce the topsoil needed to make other types of plants stronger. After its cultivation, the soil is completely free of weeds as well as being in excellent condition thanks to the reclaiming of the topsoil. This is confirmed by the study of Bócsa and Karus (1998), which shows that hemp has increased wheat yields by up to 20%.

In addition, the roots of hemp go deep down, protecting the soil from run-off and providing greater levels of stability. This is all thanks to hemp's branching taproots, consisting of a main root that can reach up to 2.5 metres and secondary roots 60-80 centimetres long.

Ultimately, hemp regenerates the soil on which it is cultivated by improving its productivity by up to 40 per cent compared to flax, which, on the other hand, has a negative impact on the soil considering its higher soil requirement. Moreover, as the growth of flax requires long rotations, it can only be grown on the same land once every 6-7 years. Otherwise, one runs the risk of impoverishing the soil and giving the green light to the proliferation of diseases.

In any case, it is interesting to note that both hemp and flax are plants capable of reclaiming heavy metal-polluted soils through phytoremediation.

5. Land requirements

From the point of view of soil requirement, hemp once again amazes. Indeed, as has been revealed by several scientific studies, the plant does not deplete the soil as flax does, so its requirements are lower when compared to other crops. This very interesting fact explains why hemp can be cultivated during several consecutive seasons without causing a negative impact on the earth.

As has been shown by Bacci (2007) flax and hemp need 100 KG/ha of nitrogen. However, the difference in requirements is observed in the amount of phosphorus and potassium. While flax needs 70 kg/ha of phosphorus and potassium to grow, hemp does not need these nutrients. It is evident, then, that the two plants have different nutrient requirements.

Although hemp is indeed less in need of substances from the earth, it should not be forgotten that flax has much lower nutrient requirements than other plants such as cotton or wheat. All this leads to the fact that fewer herbicides and pesticide treatments have to be used.

6. Fertiliser

Unlike flax, hemp is often included in the flax crop rotation scheme because it does not need fertilisers and pesticides. Hemp also helps combat the proliferation of weeds.

In fact, it should be noted that hemp is hardy and this allows it to grow on different types of soil without being susceptible to disease. Flax, on the other hand, is a more delicate plant and that is why it needs fertilisers to be cultivated.

7. Organic fertiliser

With regard to the use of organic fertilisers, hemp reacts very well. Thanks to the application of these types of fertilisers, which slowly release nutrients into the soil, the plant is able to absorb them most efficiently. Among the most recommended organic fertilisers are nutrient-rich compost, animal fertilisers (manure, guano, etc.) and minerals.

8. Biomass

As mentioned earlier, hemp provides a higher fibre yield than flax. This translates into a high biomass to convert the unburnable flat in the form of alcohol. It is also important to say that hemp grows much taller than flax, on average 2 to 4 metres depending on the latitude where it is grown, whereas flax reaches a maximum height of 1.20 metres.

As pointed out by Höppner and Menge-Hartmann, (2007) hemp has a biomass yield of 8-14tonne/ha while, on average, flax is able to produce 5-7 tonnes of biomass. This means that, when comparing both crops, hemp yields larger quantities of higher quality long fibres.

9. Water consumption

If we compare water requirements, what is surprising is the fact that both hemp and flax do not need large irrigation systems as cotton does. As Pierluigi Fusco Girard, managing director of the Linificioe Canapificio Nazionale, stated, if 150,000 hectares of flax cultivation in France were replaced by cotton, the water requirement would increase by 100 million litres within a year, i.e. the requirement of a reason like Calabria. [2]

These surprising data make it clear why it is absolutely imperative to transform the way we dress and use fabrics, promoting the production of hemp and linen for this sector.

10. Climatic needs

The last difference between flax and hemp that we want to tell you about in today's article has to do with climatic requirements. For its part, hemp is one of the most versatile natural plants that exist in nature. Thanks to its adaptability, it can be planted and cultivated in areas characterised by different types of climate.

As Lisa Zampollo (2022) points out, hemp can grow at 1000 metres above sea level in Piedmont, but also in the south of Italy at lower altitudes, without being affected or reducing its fibre yield. Having said this, in any case, it is good to know that the most favourable climate for hemp is the hot and humid characteristic of temperate regions that favour the production of large organic masses.

Instead, to cultivate flax, it is necessary to locate land where the climate is mild and humid in order to ensure a good level of maceration. This does not have to be the case with hemp, whose hardy plant adapts to the climate of the cultivation area. Finally, it is also possible to cultivate winter hemp, intended mainly for fibre use, where the plant does not reach a height of 4 metres and the yield per hectare is lower, but nevertheless the quality obtained for textiles is interesting.

Sources and insights:

[1] Piotrowski S., Carus M., Ecological benefits of hemp and flax cultivation and products, 2011Link

[2] Gregoire M. et al, Comparing flax and hemp fibres yield and mechanical properties after scutching/hackling processing, Industrial Crops and Products, Volume 172, 15 November 2021, 114045, Link

[3] https://www.vestilanatura.it/canapa-e-lino-a-confronto/

[4] https://lampoon.it/articolo/25/04/2022/lino-canapa/

[5] https://agronotizie.imagelinenetwork.com/materiali/Varie/File/Mario_Rosato/manuale-coltivazione-lavorazione-lino-ramie-kenaf.pdf

[6] Zampollo L., Valutazione sulla sosteniblità nella produzione dei semi di canapa, 2022 Link

Photo:

[1] Steva Hemp, Foto di Luca Guadagnini

[2]

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